Spotify announced Thursday it’s testing a new voice-enabled ad experience on mobile to give listeners the ability to interact with content using voice commands.

For now, the streaming service is experimenting with the format to direct listeners to branded or original content. The initial test ads promote a branded playlist from Unilever’s Axe and Spotify Studios’ original Clash podcast.

How it works. When a voice-enabled ad is served, listeners can opt to engage with it by responding, “Play Now.” That voice command activates the playlist or podcast, which also contain additional ads. If the listener doesn’t respond or says something other than the “Play Now” command, the current audio content will resume as usual.

The ads will only be served to a subset of users in the U.S. who have microphone permissions granted in their settings and are streaming from the free, ad-supported version of Spotify. Users can opt out.